Trying to figure out exactly how long will propane last in rv trips is basically a rite of passage for every new camper. You're out there in the woods, the sun is going down, and suddenly you realize you have no idea if you have enough gas to make it through the night. It's a common worry because propane is essentially the lifeblood of a rig when you aren't plugged into shore power. It runs the fridge, heats the water, and most importantly, keeps the furnace kicking when the temperature drops.
The short answer is that it depends entirely on what you're doing and the weather outside. A single 20-pound tank could last you anywhere from two days to an entire month. I know that's a huge range, but once you break down how different appliances eat through your supply, you can start to predict your own usage with a lot more confidence.
Breaking Down the Variables
Before we can estimate how long your supply will hold up, we have to look at the gear you're carrying. Most travel trailers and fifth wheels come with either 20-pound or 30-pound tanks. A 20-pound tank is the standard size you see on backyard BBQ grills, and it holds about 4.7 gallons of propane. A 30-pound tank is taller and holds roughly 7 gallons.
If you have a dual-tank setup, you've got double that capacity, which gives you a nice safety net. But having the gas is only half the battle; knowing how fast you're burning it is where things get tricky. Propane usage is measured in BTUs (British Thermal Units). One gallon of propane contains about 91,500 BTUs. To figure out your "burn rate," you just look at the BTU rating of your appliances and do a little bit of mental math.
The Appliances and Their Appetite
Not all appliances are created equal. Some are "sippers" that barely make a dent in your tank, while others are "gulpers" that can drain a bottle before you even realize what happened.
The RV refrigerator is the ultimate sipper. Most modern RV fridges that run on propane are incredibly efficient. They use a tiny flame to circulate the coolant. If you're just running the fridge on propane while you're boondocking, a single 20-pound tank could easily last you three weeks or even a month. It's almost negligible in the grand scheme of things.
Cooking is also relatively low-impact. Unless you're baking a sourdough loaf in the RV oven every single day, your stovetop burners won't use much gas. Most people find that cooking three meals a day barely moves the needle over the course of a week.
The water heater sits somewhere in the middle. It takes a decent amount of energy to heat 6 or 10 gallons of cold water. However, once the water is hot, it doesn't take much to keep it there. If you leave the water heater on 24/7, you'll burn through gas faster. If you only turn it on 20 minutes before you need a shower, you'll save quite a bit.
The Furnace is the Real Culprit
If you want to know how long will propane last in rv tanks during the winter, you have to look at the furnace. This is the heavy hitter. Most RV furnaces are rated between 20,000 and 40,000 BTUs.
Let's say you have a 30,000 BTU furnace. If that furnace ran continuously for one hour, it would consume about one-third of a gallon of propane. In really cold weather, where the furnace is cycling on and off frequently, you could easily burn through a gallon or two in a single night.
I've been in situations where the temp dropped into the teens, and we went through a full 20-pound tank in just about two days. It's a shock the first time it happens. You wake up, the rig is freezing, and you realize the "auto-changeover" regulator has already flipped to the second tank. If you're planning on winter camping, you have to prioritize insulation, or you'll be making trips to the propane refill station every other morning.
Estimating Your Usage in the Real World
To give you a better idea of what to expect, let's look at a few common scenarios.
If you're summer camping and only using propane for the fridge and occasional cooking, a 20-pound tank will likely last you 2 to 4 weeks. Most of your heavy energy use in the summer—like the air conditioner—runs on electricity anyway, so your propane stays mostly untouched.
If you're shoulder season camping (think spring or fall) where the days are 60 degrees but the nights drop to 40, you'll probably be running the furnace for a few hours in the morning and evening. In this scenario, you can expect a tank to last about 7 to 10 days.
Now, if you're boondocking in the winter, all bets are off. If you're relying solely on that furnace to keep the pipes from freezing and the cabin comfortable, you're looking at 2 or 3 days per tank. This is why many full-timers who stay in cold climates invest in "Extend-a-Stay" kits that let them hook up a massive 100-pound external tank.
How to Stretch Your Propane Supply
Since nobody likes running out of gas in the middle of a rainstorm, it helps to have a few tricks up your sleeve to make that propane last longer.
First off, if you have hookups at a campsite, use an electric space heater. Most campsites include electricity in the nightly fee, so why burn your expensive propane when you can use their power? A small ceramic heater can keep the main living area of an RV surprisingly toasty, meaning your furnace won't have to kick on nearly as often.
Another huge help is an electric heat strip or a heat pump if your AC unit has one. Again, this uses the park's electricity instead of your gas. However, keep in mind that these don't usually blow air into the "basement" or underbelly of the RV. If it's truly freezing outside, you still need to run the furnace occasionally to keep your plumbing from freezing.
For the water heater, if you have a "standard" RV water heater, it likely has both a gas and an electric switch. Use the electric side whenever you're plugged in. You'd be surprised how much gas you save just by making that one simple switch.
Lastly, insulation is your best friend. Using Reflectix in the windows, putting a pillow in the roof vents, and using heavy curtains can trap the heat inside. The less heat that escapes, the less your furnace has to work, and the longer that propane stays in the tank.
Keeping Track of Your Levels
One of the most frustrating things about RV propane tanks is that the gauges are notoriously unreliable—or they don't have gauges at all. Many people use the "hot water trick," where you pour a cup of hot water down the side of the tank. The part of the tank with liquid propane inside will feel cold to the touch, while the empty part will feel warm. It's an old-school method, but it works in a pinch.
If you want something more high-tech, there are magnetic sensors you can stick to the bottom of the tanks that sync to your phone via Bluetooth. They give you a pretty accurate percentage of what's left. For anyone doing a lot of boondocking, these are worth their weight in gold because they take the guesswork out of the equation.
Final Thoughts on Propane Longevity
At the end of the day, figuring out how long will propane last in rv life is something you'll get a feel for over time. You'll start to notice the sound of the furnace and know exactly how much gas it's drinking. You'll learn that you don't need the water heater on all day just to wash a few dishes.
The biggest takeaway is to always have a backup plan. If your rig has space for two tanks, always keep both of them full when you head out. Don't rely on just one, thinking it "feels heavy enough." Propane is one of those things where it's much better to have it and not need it than to be hunting for a Tractor Supply or a gas station at 9 PM on a Sunday. Once you get your system down, you can stop worrying about the gauges and start enjoying the view.